This application claims the benefit of Korean Patent Application No. 2002-7015 filed on Feb. 7, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an organic electroluminescent (EL) display device, and more particularly, to an organic electroluminescent display device having improved manufacturability, a substrate of the same and a method of cutting the substrate.
2. Description of the Related Art
Recently, much attention has been paid to electroluminescent display devices as spontaneous emission display devices because they have advantageous features suitable for next generation display devices, such as a wide viewing angle, a high contrast ratio and a high response speed. Electroluminescent display devices are classified into inorganic electroluminescent display devices and organic electroluminescent display devices according to materials to form emitter layers. Organic electroluminescent display devices have good luminance and a high response speed and are capable of achieving full-color display.
Generally, an organic electroluminescent display device (to be abbreviated as an organic EL device, hereinafter) is configured such that a positive electrode layer with a predetermined pattern is formed on a glass or other transparent substrate. Then, organic layers and a negative electrode layer with a predetermined pattern are sequentially stacked on the positive electrode layer in a direction orthogonal to the positive electrode layer. Here, the organic layers have a layered structure of a hole transport layer, a light emitting layer and an electron transport layer that are sequentially stacked, and these layers are made from organic compounds.
Usable materials for the organic layers include copper phthalocyanine (CuPc), N,Nxe2x80x2-di(naphthalene-1-yl)-N,Nxe2x80x2-diphenyl-benzidine (NPB) and tris-8-hydroxyquinoline aluminum (Alq3).
In the above-described organic EL device, where a drive voltage is applied to the positive electrode and the negative electrode, holes from the positive electrode migrate to the light emitting layer via the hole transport layer, and electrons from the negative electrode migrate to the light emitting layer via the electron transport layer. The holes and the electrons are recombined in the light emitting layer to generate excitons. As the excitons are deactivated to a ground state, fluorescent molecules of the light emitting layer emit light, thereby forming an image. U.S. Pat. Nos. 6,452,576 and 6,390,874 disclose such organic EL devices.
To mass produce organic EL devices, as shown in FIG. 1, a plurality organic light emitting portions (not shown) are formed on a large base panel 12 at a predetermined interval. The respective organic light emitting portions are encapsulated by encapsulation caps 13, and first and second groups of electrodes 14 and 15 drawn out from at least one of each end of the respective encapsulation caps 13 are patterned, thereby manufacturing a substrate 10 having the organic EL devices. The manufactured substrate 10 is cut at portions between neighboring encapsulation caps 13, thereby producing a plurality of individualized organic EL devices 11.
FIG. 2 shows a detailed diagram of the substrate 10 shown in FIG. 1. As shown in FIG. 2, the first and second groups of electrodes 14 and 15 are drawn from one edge of each of the encapsulation caps 13 which encapsulate the respective organic light emitting portions. The first and second groups of electrodes 14 and 15 apply voltages to positive and negative electrodes (not shown) which constitute the organic light emitting portions. A wide dead space 16 is provided between an end portion of electrode terminals of the first and second groups of electrodes 14 and 15 and an edge of an adjacent encapsulation cap 13, to then be easily cut along a cutting line A1. Additionally, the substrate 10 is cut along another cutting line A2. Thus, the substrate 10 is partitioned into the plurality of organic EL devices 11. To remove the dead space 16, the partitioned organic EL devices 11 may be further cut along a cutting line B, which lowers working efficiency, resulting in poor manufacturability.
Patterns of the respective electrode terminals of the first and second groups of electrodes 14 and 15 and the positive and negative electrodes connected thereto are inspected whether they are short-circuited or disconnected. In the substrate 10 of the organic EL device shown in FIG. 2, the respective organic EL devices obtained by primary cutting are individually inspected. However, individually inspecting the respective organic EL devices lowers working efficiency, resulting in poor manufacturability and requiring an increased work force and inspection facility.
FIG. 3 shows another example of a substrate 30 of an organic EL device to illustrate an inspection operation performed in terms of a unit substrate. First and second groups of electrodes 34 and 35 are drawn from respective one-side edges of encapsulation caps 33 which encapsulate a plurality of organic light emitting layers (not shown) provided on a single base panel 32 at a predetermined interval.
A wide dead space area 37 is provided between end portions of electrode terminals of the first and second groups of electrodes 34 and 35 and an edge of an adjacent encapsulation cap 33, to then be cut along a cutting line C1. Also, a common electrode 36a is formed at an end portion of electrode terminals of the first group of electrodes 34. The respective electrode terminals are all electrically connected by the common electrode 36a. A common electrode 36b is also provided at an end portion of electrode terminals of the second group of electrodes 35. After the organic EL devices are inspected through the common electrodes 36a and 36b, the substrate 30 is cut along cutting lines C1 and C2. To eliminate the electrically connected state and remove the dead space area 37, the substrate 30 is further cut along a cutting line D in parallel with the common electrodes 36a and 36b, thereby finally producing the individualized organic EL devices 31. However, similar to the substrate 10 of FIG. 2, the substrate 30 also requires an additional cutting operation to be partitioned into the plurality of organic EL devices 31, which lowers a working efficiency and results in poor manufacturability.
Accordingly, it is an aspect of the present invention to provide an organic EL device having first and second groups of electrodes which minimize inspection and cutting operations thereof, a substrate of the organic EL device and a cutting method of the substrate. Therefore, the present organic EL device increases the manufacturability thereof.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
To achieve the above and/or other aspects of the present invention, there is provided an organic EL device comprising a substrate, an organic light emitting portion which includes a positive electrode formed in a predetermined pattern, an organic layer formed on the positive electrode, and a negative electrode having a predetermined pattern in a direction orthogonal with the positive electrode, an encapsulation cap which encapsulates the organic light emitting portion, first and second groups of electrodes which are drawn out from at least one edge of the encapsulation cap and connected to the positive and negative electrodes, respectively, to drive the organic light emitting portion, and first and second dummy electrodes formed at one side of the substrate.
To achieve the above and/or other aspects of the present invention, there is provided a substrate of an organic EL device, the substrate comprising a single transparent base panel, organic light emitting portions formed on the base panel at a predetermined interval, encapsulation caps which encapsulate the respective organic light emitting portions, and first groups and second groups of electrodes which drive the respective organic light emitting portions. Each pair of the first group and second group of electrodes includes first and second electrode terminals, respectively, which are drawn out from one or more edges of a corresponding one of the encapsulation caps, and first and second dummy electrodes, respectively, which extend from the first and second electrode terminals to a dead space between the corresponding encapsulation cap and one or more adjacent encapsulation caps, wherein ends of the first and second dummy electrodes are patterned to be connected to one or more adjacent organic light emitting portions so as to inspect the substrate in terms of a unit substrate whether the first and second electrode terminal s are short-circuited or disconnected.
To achieve the above and/or other aspects of the present invention, there is provided another substrate of an organic EL device, the substrate comprising a single transparent base panel, organic light emitting portions formed on the base panel at a predetermined interval, encapsulation caps which encapsulate the respective organic light emitting portions, and first groups and second groups of electrodes which drive the respective organic light emitting portions. Each pair of first group and second group of electrodes includes first and second electrode terminals, respectively, which are drawn out from one or more edges of a corresponding one of the encapsulation caps, and first and second dummy electrodes, respectively, which extend from the first and second electrode terminals to a dead space between the corresponding encapsulation cap and one or more adjacent encapsulation caps.
To achieve the above and/or other aspects of the present invention, there is provided still another substrate of an organic EL device, the substrate comprising a single base panel, organic EL devices formed on the base panel at a predetermined interval so as to be partitioned into two or more areas, and first groups and second groups of electrodes which drive the respective organic EL devices and include first and second electrode terminals which are drawn out from the respective organic EL devices in a matrix type so as to sequentially and electrically connect the first and second groups of electrodes provided at each of the organic EL devices in each area to first groups and second groups of electrodes of adjacent organic EL devices, thereby allowing an inspection by the first and second groups of electrodes of the outermost organic EL devices in each area whether the first and second groups of electrodes are short-circuited or disconnected.
To achieve the above and/or other aspects of the present invention, there is provided yet another substrate, the substrate comprising a single base panel, organic EL devices formed on the base panel at a predetermined interval to form a matrix, groups of electrodes which drive and are drawn out from the respective organic EL devices, groups of lead terminals which are formed between the organic EL devices that are arranged in a line, and connected to corresponding ends of the groups of electrodes so as to have each group of lead terminals be connected to a corresponding group of electrodes, and one or more groups of external terminals which are provided for each area of the matrix, wherein each group of external terminals is electrically connected to the groups of lead terminals in a corresponding area of the matrix, and includes inspecting terminals at ends thereof.
To achieve the above and/or other aspects of the present invention, there is provided a method of cutting a substrate having organic EL devices, the method comprising producing the substrate including forming organic light emitting portions on a single transparent base panel of the substrate at a predetermined interval, fixing encapsulation caps to encapsulate the organic light emitting portions onto the base panel, and patterning first and second groups of electrodes including first and second electrode terminals drawn out from one or more edges of each of the encapsulation caps to drive the organic light emitting portions, and first and second dummy electrodes extending from the first and second electrode terminals into dead space areas between the encapsulation caps and adjacent encapsulation caps, and cutting a portion between each of the encapsulation caps so as to partition the organic EL devices into a plurality of unit organic EL devices.
In the present invention, the first and second electrode terminals of the first and second groups of electrodes can be inspected in terms of a substrate whether they are short-circuited or disconnected. Also, an organic EL device of the present invention has an improved manufacturability because an additional cutting operation to remove a dead space can be avoided.